Vitamin C Stone Risk — ESENeph MCQ

Correct answer: D — Stop pharmacological vitamin C to reduce excess urinary oxalate

The best answer is “Stop pharmacological vitamin C to reduce excess urinary oxalate”. High-dose vitamin C is a modifiable oxalate source; normal dietary calcium with meals can bind intestinal oxalate, whereas indiscriminate calcium restriction may be counterproductive. “Increase vitamin C after confirming recurrent calcium-oxalate stones” is less appropriate because high-dose ascorbate is metabolized to oxalate and may worsen risk “Replace dietary fruit with standardized high-dose vitamin supplements” is less appropriate because the concern is pharmacological high-dose supplementation, not normal dietary intake “Continue low-dose dietary vitamin C while avoiding pharmacological doses” is less appropriate because the relevant effect is increased oxalate exposure “Maintain normal dietary calcium to support intestinal oxalate binding” is less appropriate because low dietary calcium can increase intestinal oxalate absorption

Reference: EAU guideline on urolithiasis: https://uroweb.org/guidelines/urolithiasis/chapter/guidelines